Communication networks can be built in many different network topologies, such as a ring, mesh, linear, linear chain, tree, and the like. Conventionally, network protection is provided for at layers one and below, such as through SONET, SDH, and the like. Typical protection schemes can include Automatic Protection Switching (APS), Uni-directional Path Switched Rings (UPSRs), two and four fiber Bi-directional Line Switched Rings (BLSRs), and the like. Traditionally, networks are typically not protected using ring protection schemes at layer two (e.g., Ethernet) and above. For example, Ethernet-based access and aggregation networks are typically designed in a tree structure, and thus lack network protection and has only restoration mechanism.
Modern networks, such as access and aggregation networks, are moving towards Ethernet as the universal medium. Ethernet standards are evolving towards carrier-grade performance, and equipment providers today provide various different solutions for Ethernet-based network protection. For example, layer one protection can be provided through Ethernet-over-SONET or Ethernet-over-SDH solutions. To increase the bandwidth with the Ethernet-over-SONET and Ethernet-over-SDH leads to higher cost. At layer two, various solutions have been presented, such as Rapid Spanning Tree Protocol (RSTP), and Spanning Tree Protocol (STP). The major problems with this type of path protection scheme are: (1) switching time in response to a fault is relatively slow, (2) cannot offer QoS because of in-deterministic tree; and (3) complex circuitry (4) hop-count limitation.
Another form of providing protection switching in a layer-2 network is an Ethernet Ring Protection Switching (ERPS) which is formed only of Ethernet bridges as per ITU-T G.8032v1 or v2. This network protection scheme is only restricted for bridges/switches within the chain or loop of the network.
Whenever, the network has to expand i.e. for a Metropolitan Area Network (MAN), the protection scheme has to include one or more aggregation devices for data transfer. The standard ITU-T G.8032 is for Layer 2 Ethernet device. It is also possible to protect ring protection work or ERPS for Non-ERPS devices by appropriately setting a Remote Destination Indication (RDI) bit in the Continuity Check Message (CCM) generated from one of the node and transmits the same via the non-ERPS device or through the non-ERPS device or over a disjoint communication channel and also blocking the port of the node towards the non-ERPS device upon receipt of the fault notification and transmitting signal fail notification message on both the ports in the ring that connects non-ERPS devices. But these setting leads to certain limitations, primarily ERPS will form loop if dual homed with VPLS network and also need extra functional support to avoid it, and secondly ERPS message has to pass through IP/MPLS cloud, where the IP/MPLS nodes do not understand these messages and may discard the same (non-deterministic).
For the reasons stated above, which will become apparent to those skilled in the art upon reading and understanding the specification, there is a need in the art for a protection switching method in a communication network, where the communication network having one or more of communication devices forming a linear chain and at least one non-Ethernet Ring Protection Switching (ERPS) device connecting terminal ports of the linear chain and thereby forming a ring.